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An important tool is now available to all scientific and industrial participants in the Gaia mission: the Gaia Parameter Data Base. This is an ESA-supplied centralised, on-line, searchable repository of parameters pertaining to the mission and its different elements. It comprises a large variety (many hundreds) of entities ranging from simple scalar numerical constants to multi-dimensional data sets, subdivided into categories, and approved by the GST and relevant working groups.
For example, the "Nature" category contains the adopted values of fundamental physical and mathematical quantities, masses of objects in the solar system, the thermal expansion coefficient of SiC at the operational temperature, etc. The instrument category contains parameters like pixel sizes, QE/MTF, readout rates and readout noise of the CCDs, dimensions of the optics, satellite spin rate, mirror reflectivities as a function of wavelength, etc.
The data base can be interrogated in two modes: (i) a browse mode when searching for a specific quantity or when a structural overview is sought; (ii) a search mode where a download of all parameter values, or all parameters in a specific category, can be requested. Query results can be returned in HTML (Web browser) format, or in formats suitable for usage with program source code in Fortran (77 or 90), Java, C, C++, or XML. Also, contents rendering to a number of other formats such as PDF is supported.
The goal of the Gaia Parameter Data Base is to have a controlled, up-to-date repository of all parameters (with naming convention) which can be adopted consistently across the project. Versioning control is implemented. The Simulation Working Group and telemetry modeling effort are already using the data base, and GDAAS will move to using it soon. We encourage all involved in Gaia to investigate and use this data base as the primary source for all parameter values. Users are strongly encouraged to report errors, inconsistencies, or omissions.
The data base is accessible on-line at http://www.rssd.esa.int/Gaia/paramdb/. Access is via My Portal. Any individual working on Gaia can request a username/password for My Portal from the Gaia Help Desk.
The image above shows a screen shot of the search interface.
[Published: 26/04/2004]
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